1. Field of the Invention
The present invention relates to storage vessels and, more particularly, to transportable liquid storage tanks having corrugated sidewalls.
2. Description of the Prior Art
U.S. Pat. No. 3,131,949 describes a self-sustaining tank for transporting liquids, primarily to and from oil and gas depots. Such tanks contain relatively small volumes and are permanently mounted on wheels. They are not adapted for storage purposes and, because of their smaller size, sidewall strength is not a major problem.
Vessels used for storage of heavy liquids in relatively large volumes are commonly mounted on foundations. They typically involve permanent reinforced structures having large side beams, peripheral tie rods and the like. Size and weight are not overriding design considerations.
Unfortunately, the above vessels do not satisfy the need for temporary on-site storage means. Relatively large volume vessels are needed for use at oil well drilling sites, construction sites, fire fighting locations and in-situ chemical processing operations. Here, the vessel must be capable of being transported to the site while being large and strong enough to effectively contain the desired liquids.
For those vessels having a capacity in the range of 100 to 700 barrels, sidewall strength and the manner of achieving it become a major consideration. This is especially true when the liquids being contained are heavy--such as oil well drilling fluids having a density on the order of 140 pounds per cubic foot. Existing noncylindrical portable tanks capable of holding such fluids require much internal reinforcement to be self-sustaining. Typically, such tank interiors have multiple beams and tie rods extending vertically and horizontally between floor, roof and opposing sidewalls. In effect, an internal maze is created making cleaning and maintenance an almost impossible task.
When cleaning is difficult, corrosion will become a problem. As corrosion weakens the internal reinforcements, the tank becomes unsafe and not suitable for its intended purpose.